1. Field of the Invention
The invention relates to a digital device for initializing an integrated circuit.
2. Brief Description of the Prior Art
Modern integrated circuits include, within their numerous layers of integration, a multitude of active elements allowing complex functions to be carried out.
The supplying of these active elements with power poses numerous problems, such as in particular, under steady conditions, the provision of a stable supply voltage free from too large a noise level.
Although these problems have formed the subject of numerous studies following which it has been possible to propose various solutions, another problem with the implementation of these circuits results from the existence of a disordered setup of the values of supply voltage at the various nodes of this type of circuit as well as the untimely appearance of uncalibrated clock signals during this setup period. The effect of these phenomena is to cause a malfunction of these circuits and it is necessary to provide initialization circuits permitting the effects thereof to be reduced.
Among the solutions adopted, the most conventional consist overall in detecting the instantaneous value of the supply voltage to the whole of the integrated circuit, and in then comparing this instantaneous value with one or more threshold values, so as to introduce, by way of appropriate delay circuits, adapted sequential control of the value of the supply voltage applied at nodes or essential points of the integrated circuit.
Such devices, which are known as RESET circuits, which adopt analog solutions, prove satisfactory. However, by virtue of their essentially analog character these types of devices which first and foremost involve capacitance and resistance circuits, cannot easily be subjected to an integration process actually within the integrated circuit. The silicon area expended in order to integrate such circuits is in fact prohibitive for a component or element which acts first and foremost as a passive component with regard to the integrated circuit proper.